The Commonwealth of Massachusetts "defines open formats as specifications for data file formats that are based on an underlying open standard, developed by an open community, affirmed and maintained by a standards body and are fully documented and publicly available."[5]

According to The Linux Information Project, the term open format should refer to "any format that is published for anyone to read and study but which may or may not be encumbered by patents, copyrights or other restrictions on use"[1] – as opposed to a free format which is not encumbered by any copyrights, patents, trademarks or other restrictions.